External

Bismuth salts have no action on the unbroken skin. Dusted on a raw surface they form a protecting coat, are germicidal, and are very mildly astringent. For this purpose the tribromophenolate and subgallate, the latter also known as dermatol (both unofficial), are preferable.

Internal

If large doses of bismuth salts are injected under the skin of animals, or if large doses of soluble salts are given to them by the mouth, they produce effects as severe as those due to antimony. The chief are gastro-intestinal irritation and fatty degeneration, and it is stated that some very susceptible persons may be poisoned by large doses by the mouth of insoluble salts; but, as a rule, any symptoms of gastro-intestinal irritation caused by the insoluble bismuth salts are due to the arsenic with which they may be contaminated. When pure, it is probable that these salts, like any bland heavy powder, act chiefly as protec-tives to the gastro-intestinal mucous membrane; for gastric ulcer the subnitrate is to be chosen. They have an astringent action, diminishing secretion, and are especially the naphtolate (not official) gastro-intestinal antiseptics. Bismuth is slowly absorbed and excreted in the urine Bergeret and Mayencon, and it may be found in the liver, spleen, kidneys, and nervous system. Nothing is known of any remote effects. Bismuth leaves the rectum as the sulphide, and colors the faeces black. It may cause a purplish line on the gums.

Therapeutics of Bismuth Salts

External

Bismuth salts may be dusted on sores as protec-tives and mild astringents. The following is a good bismuth ointment: - Bismuth oxide official in B. P. 1 part, and oleic acid 8 parts, stirred in with 3 parts of white wax liquefied by heat, and with 9 parts of soft paraffin. The subnitrate is sometimes snuffed up the nose during a cold, and suspended in mucilage it may be used as an injection for gonorrhoea or leucorrhcea. Internal. - The subnitrate and the subcarbonate are chiefly employed, and they seem to be more efficient than the soluble preparations. Soluble bismuth salts when absorbed are likely to act as active irritant poisons, and for this reason should not be used. The insoluble preparations must be suspended in mucilage of tragacanth, for with acacia a compact mass is formed at the bottom of the bottle; given thus they are more efficacious than as a lozenge. It is not known how the effect is produced, but either of these salts is remarkably efficient in removing gastric pain, whether due to ulcer or to gastritis, or even when no cause can be detected. Both of these drugs will often stop the vomiting due to gastritis, gastric ulcer, chloroform, pregnancy, or indeed any other cause. For their astringent action they are given in diarrhoea, doses of 60 gr. 4. gm. being administered without any ill effect, and some believe that part of the benefit is due to the antiseptic action of bismuth salts. They appear sometimes to check the severe diarrhoea of tuberculous ulceration of the bowel. For internal use the phe-nolate and naphtolate (neither are official) are preferable to the inorganic salts. They are employed in the same dose. Their efficacy as gastric anodynes and gastric astringents is much increased by combination with a little morphine, and if given as gastric sedatives the addition of sodium bicarbonate as well as the morphine is an advantage. In such a prescription the bismuth subcarbonate is preferable to the subnitrate, for the latter may act on the sodium bicarbonate and lead to the production of sufficient carbon dioxide to drive the cork out of the bottle. The salicylate has been largely used in various gastric disorders. It is supposed to combine the virtues of bismuth salts with the antiseptic action of salicylic acid. Bismuth salicylate probably passes through the stomach unchanged to be broken up in the small intestine where it acts as an unirritating antiseptic. It has been proved to be a valuable remedy in the treatment of diarrhoeas, typhoid fever and catarrhs of the alimentary tract. Heuppe's observations in Asiatic cholera prove that the tribro-mophenolate is a valuable intestinal antiseptic. Bismuth sub-gallate (dermatol) was formerly much employed in the treatment of gastro-intestinal indigestion, but has been supplanted by the more efficient naphtolate and tribromophenolate.

Eudoxin (not official) is bismuth tetra-iodophenol-phthaleinate, and occurs as a tasteless, odorless, reddish-yellow, insoluble powder. This is decomposed in the intestines, and is claimed to be a germicide. It is certainly known that iodine is liberated. It is employed as an intestinal antiseptic in dose of from 5 to 8 gr.; .30 to .50 gm.

Toxicology

When applied in large quantity to an exterior wounded surface sufficient bismuth may be absorbed to produce poisoning. This may also occur if glycerin is used to form an emulsion for injection into closed cavities (abscesses, joint-disease).

Symptoms

These are acute stomatitis with a peculiar blackish discoloration of the mucous membrane, generally upon the borders of the teeth and extending over the whole mouth, ulceration of the mucous membrane, intestinal catarrh, pain and diarrhoea. Even desquamative nephritis may be set up.

Treatment

Use demulcents.